Preheat oven to 450°F. Wash, core and cut tomatoes in halves.

Lightly coat baking tray with nonstick spray and spread tomatoes, garlic cloves & onion onto baking tray. Drizzle 1/4 cup olive oil and season with salt & pepper.

Roast until caramelized which should be about 20 to 25 minutes.

Transfer the roasted tomatoes, garlic and onions to a large stock pot, add 3/4 of chicken stock, bay leaves & butter.

Bring to boil, then reduce heat and simmer for about 20 minutes, uncovered or until liquid has been reduced by a third.

Remove from heat, add basil. Add salt & pepper to taste and purée.

Return to heat at low, slowly stir in heavy cream first and then remainder of chicken stock if necessary.